LG C1100 Service Manual page 61

4. Trouble Shooting
Checking Flow
Logic level at KEYON of U102
START
Yes
Check Battery Voltage
> 3.35V ?
Yes
Push power-on key and
check the level change of
U102 KEYON
Yes
Check the voltage of
the following port at U102
VOORE=1.8V ?
VMEM = 1.8 or 2.8V ?
VEXT=2.8V ?
VRTC=1.8V ?
VSIM=2.85V ?
VMIC=2.5V ?
VVCXO=2.75V ?
Yes
= HIGH?
Yes
Does it work properly?
The power-on procedure is completed.
The problem may be elsewhere.
THE PHONE WILL
POWER ON.
No
Charge or Change Battery and try again.
No
Check the contact of power-key
or dome switch.
No
Replace U102
No
Redownload software & try again.
No
Does it work properly?
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Yes
No
Yes
Replace the main board.